Ink jet recording is a process of ejecting an ink composition as small droplets through minute nozzles to record letters and images (hereinafter also simply referred to as “images”) on a surface of a recording medium. The ink jet recording processes that have come in practice include a process of converting an electric signal to a mechanical signal using an electrostrictive element, thereby intermittently ejecting an ink composition stored in a nozzle-head portion to record letters and images on a surface of a recording medium; a process of rapidly heating an ink composition stored in a nozzle head portion at a part very close to an ejection portion to generate bubbles, and intermittently ejecting the ink composition by volume expansion due to the bubbles to record letters and images on a surface of a recording medium; and the like.
Further, as an ink composition for ink jet recording, there is commonly used one in which various dyes are dissolved in water, an organic solvent or a mixed solution thereof, from the aspects of safety and print characteristics. In various characteristics, more strict conditions are required, compared to an ink composition for writing things such as a fountain pen and a ball pen.
One of the conditions includes that a clean and stable ink can be supplied so that the ink can stably flow in its passage, thereby not leading to printed image defects such as printing failure and thin spot even when the ink undergoes changes in temperature or changes with time.
However, when an elastomer resin containing a polyolefin resin is used in an ink-contacting member such as a confluence passage of the ink or a film for blocking it, it has become clear that a crystalline molecular complex is formed by the contact with the ink in some cases. This crystalline molecular complex is brittle and breaks down into an acicular form, so that it passes through a filter for trapping foreign matter to clog a minute passage of a nozzle head, which causes abnormal ejection.